Generally, the shape of tooth surfaces (actual tooth surface shape) of gears of gear pairs such as bevel gears and hypoid gears that are in practical use is not a theoretically conjugate and mathematically expressed tooth surface shape but a machinable, approximate tooth surface shape. Accordingly, it is important to perform evaluation of the strength and vibration noise of these gear pairs on the basis of tooth contact analysis of actual tooth surface shapes.
Techniques for analyzing the tooth contact of the actual tooth surfaces of such gear pairs have been disclosed. For example, Non-patent document 1 (Aizo Kubo, et al.: On Simulation Methods of Performance of Hypoid and Spiral Bevel Gears (1st Report Definition of Reference for Tooth Form Accuracy and Method of Simulation), The Japan Society of Mechanical Engineers Journal (C), Vol. 62, No. 599, (1996-1997), Article No. 95-1547, pp. 2833-2841) discloses a technique which calculates the deviation between data on actual tooth surfaces and data on reference tooth surfaces (theoretical tooth surface shape) that is set in a tooth-cutting machine during a tooth surface machining, considers the deviation as the shape deviation of actual tooth surfaces from the reference tooth surfaces, and analyzes the meshing between the actual tooth surfaces on the basis of the meshing between reference tooth surfaces.
However, the technique disclosed in Non-patent document 1 requires information about the reference tooth surfaces. Therefore, although the technique is effective for gear pairs if information about their reference tooth surfaces is available as in the case where a user for himself or herself performed a series of work from specification design to tooth surface machining, the technique is difficult to apply to gear pairs for which information about their reference tooth surfaces is not available.
That is, the technique disclosed in Non-patent document 1 requires information about the reference tooth surfaces of gears that mesh with each other. Since these reference tooth surfaces vary from machine to machine, it is difficult to evaluate the tooth contact of a real gear pair unless information about machine settings is obtained.
The present invention has been made in light of these circumstances and an object of the present invention is to provide a gear pair evaluation apparatus and a gear pair evaluation program capable of implementing accurate tooth surface analysis on the basis of actual tooth surface measurement information without using information about reference tooth surfaces, and a gear pair whose tooth surfaces are evaluated by using the apparatus and the program.